Simon Willison’s Weblog
Introducing ChatGPT Images 2.5 . OpenAI's image generation models are apparently used "more than 3 billion images across ChatGPT Images and the GPT‑Image models in the API". This latest release improves their instruction-following ability across multiple turns, responds faster, and "is better at preserving the subjects in your reference photos".
There are two new model IDs in the API: gpt-image-2.5-sunburst and gpt-image-2.5-flare . Based on this I think Sunburst is the stronger option:
Choose Sunburst for workflows where editing precision matters most, and Flare for fast, high-quality everyday image generation.
I upgraded my openai_image.py CLI tool to support passing in one or more reference images, so now this works:
uv run https://tools.simonwillison.net/python/openai_image.py \ ' add a raccoon scientist studying the chart thoughtfully ' \ -i https://static.simonwillison.net/static/2026/openai-agent-usage.webp \ -m gpt-image-2.5-sunburst
This is the original image , and here's what I got back from that prompt to "add a raccoon scientist studying the chart thoughtfully":
Recent articles
The Pelican comparison grid for Astra is pretty interesting - 4th September 2026
OpenAI's rogue agents were caught communicating via public wikis - 4th September 2026
Claude's new system prompt really doesn't want to reproduce song lyrics - 2nd September 2026
This is a link post by Simon Willison, posted on 8th September 2026 .
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